1. Field of the Invention
The present invention relates generally to an automotive vehicle having a variable suspension and power steering arrangement and more specifically to a control arrangement which simultaneously controls both the power steering system and the variable suspension system.
2. Description of the Prior Art
Japanese Patent Application First Provisional Publication 59-100,064 published in 1984 discloses a steering and suspension control arrangement which enables the suspension to be selectively set to produce either, what shall be referred to as, "hard" or "soft" characteristics and the power steering conditioned to produce "strong" and "weak" assist levels. This system has included a manually operable mode control or selection switch which can be set to either of "normal" or "sporty" modes.
With this arrangement when the mode selection switch is set to "normal" the suspension is conditioned to produce the "soft" ride while the power steering is simultaneously condition to produce a full power or strong steering assist and thus induces the so called "light" steering.
On the other hand, when the mode selection switch is set to "sporty" the suspension is conditioned to produce a "hard" (viz., firm) ride while the power steering is conditioned to produce a partial or weaker assist which induces the so called "heavy" steering.
However, this arrangement has suffered from the drawback that when the normal mode is selected the suspension can only be conditioned to "soft" and the steering to "light" and when the sporty mode is selected only the corresponding "hard" and "heavy" conditions are induced.
Thus, in the event that the normal mode is selected and it is necessary to execute a sudden maneuver such as braking or swerving to avoid a collision with another vehicle, pedestrian or the like, the suspension tends to be overly soft and permit the posture or attitude of the vehicle to change excessively (e.g. undergo substantial rolling, nose-diving etc.)
On the other hand, if the sporty mode is selected, while the harder suspension characteristics are desirable during cornering accleration/deceleration and the like type of driving, the monotonous hard ride during steady state cruising tends to detract from the driving comfort.